The analytical potential of mass spectrometry will be developed for applications to constituents of nucleic acids and their analogs. Derivatives of nucleosides which exhibit high sensitivity for electron capture negative ion chemical ionization will be prepared and studied. Models for nucleoside-carcinogen adducts will be prepared and their mass spectra examined. Applications testing of a new combined high pressure liquid chromatograph-mass spectrometer (LC/MS) will concentrate on analysis of enzymatic hydrolysates of tRNA.